1. Field
The present application relates to a medical handle having a drive unit for driving a medical tool and a control and/or regulating circuit for controlling and/or regulating the drive unit.
2. Description of Prior Art
Such handles are widely used today for a number of different medical, surgical and cosmetic procedures. The drive unit of these handles often comprises a brushless electric motor which generates a rotational movement that is transferred to a treatment tool. The drive unit may optionally have one or more shafts for transferring the rotational movement, gears or devices for converting the rotational movement into a different type of motion.
Brushless electric motors for the handles are usually controllable and in most cases the user can at least vary the rotational speed of the motor via a control element and a control device. The basic design of such a control device is diagrammed schematically in FIG. 1 of U.S. Pat. No. 5,270,622. The brushless electric motor comprises a stator, a rotor unit with a magnetic element and a sensor system for detecting the alignment of the magnetic element. The signals of the sensor system are sent to the control device, which delivers drive signals to the motor as a function of the rotational speed, as specified by the user, and as a function of the sensor signals. The sensor system is usually designed as part of the stator and is fixedly connected thereto, usually by a casting compound. The sensor system for detecting the alignment of the magnetic element and the brushless electric motor are arranged at a separate location spaced from the control device and are connected by lines for relaying the signals.
The disadvantage of such an embodiment lies in its complex design, which necessitates several steps during assembly, in particular mounting the sensor system on the stator, installing the control device in the handle and connecting the sensor system to the control device via multiple lines.
For hygienic reasons, such medical handles must be sterilized after being used, so it is necessary to protect the electric and electronic components from aggressive ambient conditions that prevail during sterilization. This is usually accomplished by casting the components in resin and/or encapsulating them in hermetically sealed housings. The points of admission of lines and cables into the cast material or the housing constitute weaknesses where leakage may occur and subsequently water vapor or corrosive media such as cleaning agents can penetrate to the electric and electronic components and damage them, resulting in premature failure of the handle and necessitating complex repair measures or complete replacement of the device, which is a disadvantage.
Finally, there is repeatedly the problem that while connecting the sensor system to the electric motor by casting with resin the insulation of the signal line between the sensor system and the control device may melt, so that satisfactory functioning of the handle is impaired. This also necessitates additional testing work after assembly to ensure that the lines are intact and/or repairs on or replacement of the lines are necessary if the lines have been damaged.
One object is therefore to create a medical handle that will not have the aforementioned disadvantages. The handle should be easy to assemble in particular and should be more resistant to the ambient conditions that prevail during sterilization than is the case with known handles.